What's more, Republicans have a chance of taking control of chambers in what have long been sapphire blue states.

"There are some members of the state Senate who were there 40 years ago when the Democrats took over," said Greg Lavelle, Republican whip in the Delaware Senate. "We think it's time for some change."

In Connecticut, Republicans are hoping voters will use their ballots to protest the policies of Gov. Dan Malloy, who has the lowest approval ratings of any Democratic governor.

"Many, many people in the state recognize the failure that is Dan Malloy and the Democratic Party," said J.R. Romano, who chairs the Connecticut Republican Party and criticized the governor for enacting a series of tax increases.

Democrats are similarly hoping that the races will serve as referenda. Only they hope voters will use the occasion to register discontent with President Trump.

"Connecticut Republicans have remained absent from the discussion about President Trump," said Michael Mandell, executive director of the Connecticut Democratic Party. "There are residents who are concerned that Republican legislators are serving as a validator for President Trump's agenda."

But the likelihood of change in Connecticut is a longshot.

Two seats are in play there, one Republican and one Democratic, and each district is likely to remain in the hands of the incumbent party. In both cases, the seats became vacant when senators were appointed to positions in state government.

The greater chance for change is in Delaware. A single seat is at stake, left vacant by Bethany Hall-Long, who was elected lieutenant governor in November.

Hall-Long is a Democrat, but her district had been represented by Republicans prior to the last round of redistricting. In 2014, Republican John Marinocame within 267 votes of unseating Hall-Long.

"I've said from day one the difference could be 200 votes," said Earl Jaques, a Democrat whose state House district overlaps with the Senate seat in play.

Marino, a realtor and former police officer, is once again the GOP's nominee. He faces Stephanie Hansen, an environmental attorney. She has derided Trump for "hate speech" and misogyny, arguing that a local victory will help sow the seeds for eventual Democratic victory over the president.

Special elections generally have low turnout, with only the most dedicated voters even aware they're occurring.

"In ordinary circumstances, you would think that would help Marino," said Paul Brewer, a pollster at the University of Delaware. "On the other hand, the election of Trump may have energized people on the left."

There's one other state where a special election might result in a change of party control this year. In Washington, Republicans have a one-seat edge in the state Senate. GOP state Sen. Andy Hill died last October. He represented a district that Hillary Clinton carried easily.

Democrats are hopeful about making a pickup, but they'll have to wait. Under state law, when a legislator leaves office, he or she is replaced by a member of the same party until a special election is held in November.

In addition, two GOP state senators have been appointed to posts in the Trump administration. Brian Dansel resigned his seat, while Doug Ericksen has not.

Like Hill, Dansel has already been replaced by another Republican. Unlike Hill, Dansel's seat will be considered safe in November. Ericksen's seat, however, is more competitive, which may be one reason he hasn't left office.

As with most legislative elections these days, it's unusual for specials to be competitive. When one party starts to make real gains, it's an early indicator that that party has real momentum heading into the next general election.

But there usually aren't many special elections that change the partisan makeup of a chamber.

"It is usually pretty rare to have a special decide control of the chamber," said David Beaudoin, editor of the blog Local & Special Elections. "The number of chambers that are up for grabs is becoming smaller and smaller, and the number of seats anywhere in the country that are up for grabs is smaller and smaller."